Heating/cooling systems

ABSTRACT

A heating/cooling system includes a plurality of solid panels which form part of a wall or floor. The panels are in the form of heating/cooling modules and incorporate a heat exchange element within the panel and in thermal contact with the material, e.g. chipboard, fiberboard or plywood, forming the panel. The panels can be provided with, for example, tongue and groove formations so that they can engage with like panels or with &#34;industry-standard&#34; panels which do not incorporate heat exchange elements.

This application is a division of application Ser. No. 08/131,127, filedOct. 4, 1993, now U.S. Pat. No. 5,497,826.

FIELD OF THE INVENTION

This invention relates to heating/cooling systems.

BACKGROUND TO THE INVENTION

There are a variety of different ways of heating or cooling a building.Examples include radiators, convector heaters, night storage heaters,fan heaters, electric radiant bar fires, warm air systems andair-conditioning.

Of these alternatives, the most widely used are radiator systems andstorage heaters. Both of these types of heating system rely on thecreation of a circulation of air within the space to be heated totransfer the heat from a local hot point--the radiator or the storageheater--to the remainder of the room, including its fittings and itsoccupants. This circulation of air, which is referred to as convection,is generated by air rising in front of the radiator or storage heater asit is heated. The warmed air rises to the ceiling before descending onthe side of the room space opposite the radiator or heater, and thenreturning across the floor of the room, to be reheated.

The disadvantages of such heating systems are well-known. The greatestaccumulation of heat is at ceiling level, away from the occupants, andthis is wasteful. The coolest air is at or near floor level and thiscauses uncomfortable draughts. In order to produce the requiredcirculation of air, the radiators or heaters have to be hot (generallybetween 80° and 85° C.) otherwise their efficiency falls rapidly, and atthis temperature the air becomes dry, causing stuffiness and drying outboth the furniture and any paintings within the room as well as thefabric of the room itself. There is also the possibility that smallchildren or elderly people who touch the radiators or heaters can sufferburns.

The advantages of such heating systems are that they are inexpensive toinstall, their technology is widely understood and the necessarycomponents are readily available.

Early electric underfloor systems, which were designed to use off-peakelectricity and which treated the floor as if it was an enormous storageheater, were uncomfortable because they heated the floor to too high atemperature in the morning but yet left it too cold in the lateafternoon and early evening.

More recent warm-water underfloor systems, which serve to circulateheated water through pipes which are set into the floor, or which useelectric cables in the floor, to gently warm the floor, are much moresuccessful. They warm the floor to a temperature approximately 3° to 4°C. higher than the ambient temperature required for the room space abovethe floor, generally to a maximum of about 25° C., so that the floordoes not actually feel hot to the touch. Yet, at this temperature, thefloor radiates a gentle overall warmth, with no draughts and with thehighest temperatures at floor level and the lowest temperatures atceiling level. Moreover, such systems maintain a higher relativehumidity than radiator or convector heater systems, which is itself moresympathetic to the room space, its contents and its occupants.

Of more recent interest, due to the rapidly escalating cost of fuels andthe increasing concern for energy conservation, is the fact thatwarm-water underfloor heating systems can be approximately 40 to 50%more energy efficient than radiator systems.

However, while such underfloor systems are accepted as beingsignificantly more comfortable and more energy-efficient thanalternative forms of heating, their single significant disadvantagehitherto has been that their initial installation cost has been higherthan for an alternative radiator system. This factor alone has beensufficient to inhibit the much wider installation of warm-waterunderfloor systems, despite the running cost and energy savings whichwould be achieved.

Market pressures on architects, developers and builders continuallydemand that the cost of building construction and refurbishment is keptto a minimum, and there have been many changes in building methods inthis pursuit.

one such change has led to the replacement of traditional floorboards inthe construction of timber floors by mass-produced panels of particulatechip-board or fibre-board. While there are underfloor heating systemswhich can be fitted between the floor joists below such floor panels,and which work completely satisfactorily, they are expensive to installand consequently they are only fitted in buildings where comfort isspecified as a specific and particular objective.

Another such change is the move away from solid floor constructions, inwhich a fine screed of 50 to 100 mm. thickness is put on top of aconcrete raft or block and beam construction, towards a floorconstruction which includes a layer of high-density foam insulationplaced directly on top of the concrete raft or the block and beam, withthe insulation layer then being covered by a floating layer ofparticulate chipboard or fibreboard panels. The panels are produced asstandard sizes, for example, 18 mm. or 22 mm. in thickness, 600 mm. inwidth and 2400 mm. in length. Reasons for this change include not onlyreduced cost but also improved sound insulation and the elimination ofthe "wet trades" associated with having to lay the screed.

Paradoxically, this move away from a solid, screeded floor constructionmethod, into which known underfloor heating systems could beincorporated most efficiently, towards a type of floor construction intowhich it has hitherto been most difficult to incorporate underfloorheating, will potentially reduce still further the number of newunderfloor heating installations and the energy savings which they wouldhave made.

It is accordingly a specific object of the present invention to providea method of installing an underfloor heating system which is lessexpensive than the installation of a convection heating system. A moregeneral object of the invention is the provision of an improved methodof installing a heating/cooling system. Thus, although it is envisagedthat the majority of applications of the invention will be in relationto heating systems, the invention is equally applicable to coolingsystems and to systems which can provide both heating and coolingfunctions.

A further object of the invention is thus the provision of an improvedheating/cooling system.

It is known from European Patent Specification No. 0 006 683 (Neate)that underfloor heating systems can be made using small-diameter tubing(i.e. tubing having an internal diameter of between 5 mm. and 9 mm.)pre-fabricated on thermally conductive wire-mesh frameworks as modules,which can be interconnected within a heating/cooling system so that eachis connected to a flow and return supply from a heater/cooler. Wheresuch modules are installed in solid floor screeds, the screed can be asthin as 50 mm.

It is known from German Patent Specification No. 3217578 (Jung) that anarrangement of modular interconnected panels made, for example, fromchipboard, can be used to provide a continuous serpentine channel intowhich large diameter piping (i.e. having an external diameter of say 15to 22 mm.) can be laid. The serpentine channel is then covered over witha metal sheet (to aid heat distribution) and with a timber or otherfloor finish. This form of heating system can be installed either ontimber joists or laid on top of a layer of insulation laid over aconcrete structural base.

It is also known that, where a floor is formed from chipboard orfibreboard panels laid on top of a layer of insulation, which has itselfbeen laid on a concrete structural base, a serpentine recess can beformed within the top surface of the insulation into which largediameter continuous piping (i.e. piping having an external diameter ofsay 15 to 22 mm.) can be laid before the chipboard or fibreboard panelsare placed in position. Such an arrangement of continuous pipingprovides an underfloor heating system, but it is inefficient due to thepoor thermal contact between the piping and the underside of the floorand due to the large amount of heat absorbed from the piping by theinsulation itself.

In order to achieve the most effective heat transfer from the piping ortubing to the floor, an underfloor heating system as described aboverequires the piping or tubing to be surrounded with a cement-based pugor screed which is used as an inexpensive conductor. This would be usedautomatically when the piping or tubing is installed in the screed of asolid floor, but it is required even when systems are installed betweenthe floor joists below a suspended timber floor. This is due toexperience which has shown that air gaps around the piping or tubing caninhibit heat transfer and that timber strip floorboards and chipboardand fibreboard panels are not good conductors of heat. Without the pug,or some other form of heat transfer means such as a metal plate, it isdifficult to achieve the required uniform distribution of heat through atimber floor, despite the fact that the heat has only to be conductedthrough the thickness of the board.

It is accordingly a further object of the present invention to provide amethod of installing an underfloor heating system which can be carriedout more cost-effectively than existing methods of providing underfloorheating.

It is also known from German Patent Specification No. 3717577 (Kurz) toprovide a composite heating panel which includes an upper covering layerof wood to which a layer of copper wire netting is attached. The copperwire netting is bonded to a chipboard panel within which large diametercopper tubes are disposed. This panel is intended to act as a roomheater but would be too expensive for incorporation in an underfloorheating/cooling system.

A still further object of the present invention is thus the provision ofan improved form of panel for use as part of a heating/cooling system.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided amethod of installing a heating/cooling system which includes:

a) providing a plurality of solid panels, some at least of which are inthe form of heating/cooling modules and incorporate a heat exchangeelement disposed within the body of the panel and located in thermalcontact with the material forming the panel,

b) joining said panels together to form a wall or floor structure, and

c) interlinking the heat exchange elements of said modules.

The panels which are in the form of heating/cooling modules arepreferably "standard" panels, i.e. they are of such size andconfiguration that they can be fitted together with other similar panelsand with industry-standard panels to form a composite floor or wall.Thus the panels which are in the form of heating/cooling modules mayhave, along each edge, tongue and groove rebating or other means toenable them to engage with similar panels or industry-standard panels.

"Industry-standard" panels are such panels that are mass-producedindustrially for use in the building industry, typically the familiartongue and groove chipboard flooring panels which, in the UnitedKingdom, are of standard thicknesses of 18 or 22 mm., length 2400 mm.and width 600 mm. or 1200 mm.

The panels may be of bonded or laminated particulate material, such aschipboard, fiberboard or plywood, of sufficient hardness and rigidity tobe used for the upper structural surfaces of floors or for lining wallsin dwellings or other buildings. The rigidity of the panels must besufficient to enable a panel to be laid over timber joists at standardspacings, for example, 400 mm. joist centre spacings for panels 18 mm.thick and 600 mm. joist centre spacings for panels 22 mm. thick.

The heat exchange elements may comprise tubing through which a heatingor cooling fluid is passed, or electrical heating cables. The tubing ispreferably plastic tubing. Preferred plastics materials are polyamides,polyethylene and polybutylene, but other materials which are able towithstand the temperature and pressure and are not affected by theheating or cooling fluid can be used.

According to another aspect of the present invention there is provided acentral heating or cooling system comprising at least one source ofheating or cooling fluid with flow and return pipes and heat exchangemeans, wherein the heat exchange means comprises at least two heatexchange elements each incorporated within a solid panel forming part ofa wall or floor of cooperating panels and means for connecting the heatexchange elements to each other and to the source.

According to a further aspect of the present invention there is providedan electrical central heating system comprising a power source and heatexchange means, wherein the heat exchange means comprises at least twoheat exchange elements each incorporated within a solid panel formingpart of a wall or floor of cooperating panels and means for connectingthe heat exchange elements to each other and to the source.

According to a still further aspect of the present invention there isprovided a solid panel for use in the installation of a heating/coolingsystem, said panel containing a heat exchange element embedded withinits structure so as to be in thermal contact with the material formingthe panel, said heat exchange element having a thickness significantlyless than the thickness of the panel.

The heat exchange element may be serpentine and, when reference is madeto a heat exchange element being serpentine, it is meant that the heatexchange element includes at least one loop with a bend of at least180°. The or each such panel may contain a single continuous elementwith a plurality of 180° bends. It is advantageous to manufacture the oreach panel with rebates in one face along the line of the element andextending inwardly from the edge at which the element emerges from thepanel so that the ends of the element can be drawn out from the plane ofthe panel for connection to the flow and return pipes or to the powersupply when the panel is installed and joined to another panel.

In an alternative arrangement, the heat exchange elements each comprisea pair of end members interconnected by a plurality of parallel paths.Thus, for an electric central heating system, each heating element maycomprise a plastic sheet on which an electrical resistance element isprinted, said resistance element comprising a pair of relatively thick,low resistance, spaced apart end members and a large number ofrelatively thin, higher resistance connectors extending between the endmembers.

The invention further provides a method of making a panel, said methodcomprising providing two part-thickness panels, and joining thepart-thickness panels together face-to-face with a heat exchange elementsandwiched between and in thermal contact with the two part-thicknesspanels.

If the heat exchange element is in the form of a cable or tubingarranged in serpentine fashion, the serpentine heat exchange elementwill be located in a serpentine channel preformed in one or both suchfaces.

If the heat exchange element is in the form of tubing through which aheating or cooling fluid is passed, the tubing is preferably plasticstubing having an internal diameter of from 5 to 9 mm. and an externaldiameter which is not greater than 70% of the thickness of the panel.Likewise, if the heat exchange element is electric cabling, this willhave an external diameter which is not greater than 70% of the thicknessof the panel.

It will be apparent that a panel in accordance with the invention willhave insufficient strength for use in flooring applications if theembedded heat exchange element is of such diameter as to materiallyweaken the panel. Likewise, the larger the bore of the tubing, thegreater the volume of fluid contained within it and the greater thethermal inertia of the system. Conversely, a tube of less than thepreferred diameter will contain insufficient fluid to convey the desiredheating/cooling effect, unless the tube is of considerable length, inwhich case it imposes high frictional losses.

It has been found that, for panels having a standard thickness of 18mm., a 7 mm. bore plastics tube is preferred while, for panels having astandard thickness of 22 mm., a bore of 7 mm. to 9 mm. is preferred.However, it is within the capacity of those skilled in the art, giventhe disclosure hereof, to establish the optimal tube or cable size for agiven panel thickness.

The simple solid panel described herein may be incorporated in and formonly part of the total thickness of a composite flooring or wallingpanel. For example, a panel in accordance with the invention may haveeither a plain chipboard top surface or a decorative top surface formedfrom hardwood strips or thermoplastic tiles. For industrial use, thepanel may have steel decking attached to it. In a similar way, a layerof thermal and/or acoustic insulation material may be bonded to theunderside of the panel to form a composite board. Likewise, a panel inaccordance with the invention may be bonded to another panel ofdifferent or similar material to form a composite board which hasacoustic insulation properties.

The size of panel which is most commonly used is likely to be 2,400mm.×600 mm. but there are a variety of compatible sizes, to suitdifferent sizes of walls and floors. Examples include 2,400 mm.×1,200mm., 1,200 mm.×600 mm. and 600 mm.×600 mm. Similarly, although the mostcommonly used thicknesses are likely to be 18 mm. and 22 mm., there area variety of other thicknesses.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first form of panel containing aserpentine heat exchange element,

FIG. 1A is a detail view showing an alternative arrangement for theloops of the serpentine heat exchange element,

FIG. 2 is a perspective view of a second form of panel,

FIG. 3 is a sectional view along the line X--X of the panel shown inFIG. 1,

FIG. 4 is a sectional view along the line Y--Y of the panel shown inFIG. 2,

FIG. 5 is an underneath perspective view of a corner of the panel shownin section in FIG. 3,

FIG. 6 is an underneath perspective view of a corner of the panel shownin section in FIG. 4,

FIG. 7 shows the provision of a conduit between two adjacent panels,with supply and return pipes or a power supply cable located in theconduit,

FIG. 8 shows the connection of a heat exchange element to a supply orreturn pipe or to a power supply cable when a panel is laid on top of ajoist,

FIG. 9 is a detail view showing a pipe or cable extending alongside ajoist,

FIG. 10 is a detail view showing a pipe or cable extending at rightangles to a joist,

FIG. 11 shows a typical floor panel installation,

FIG. 12 shows the connection of the panel modules of the installation ofFIG. 11 to the supply,

FIG. 13 shows another typical floor panel installation,

FIG. 14 shows the connection of the panel modules of the installation ofFIG. 13 to the supply,

FIG. 15 shows a first form of composite board,

FIG. 16 shows the installation of a second form of composite board,designed to have acoustic properties, and

FIG. 17 is an exploded view of a further form of panel in accordancewith the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 show different panel layouts and, although FIG. 3 isstated to be a sectional view of the panel 10 shown in FIG. 1, it couldalternatively be a sectional view of the panel 11 shown in FIG. 2.Equally, FIG. 4 could be a sectional view of the panel 10 shown in FIG.1.

The panels 10 and 11 shown in FIGS. 1 and 2 respectively have a width A,a length B and a thickness C, typically 600 mm., 2,400 mm. and 18 mm.Tubing or cabling 12 of serpentine configuration is embedded within eachpanel 10, 11. The embedded tubing or cabling 12 within panel 10 entersand leaves the panel at the same end, whereas the tubing or cabling 12embedded within panel 11 enters at one end and leaves at the other. Thetubing or cabling 12 within panel 10 includes five 180° bends, whereasthat within panel 11 includes only four 180° bends.

The 180° bends are spaced inwardly from the ends of each panel 10, 11 sothat sections are provided at each end of each panel 10, 11 which may betrimmed to aid fitting of the panels on site. As shown, the tubing orcabling 12 is located centrally between the two ends of each panel 10,11. It however, preferred that, for a panel 10, i.e. one in which thetubing or cabling 12 enters and leaves the panel at the same end, thetubing or cabling 12 is located closer to that end so that the length ofpanel available for trimming purposes at the other end of the panel isthereby increased. The top surface of each panel 10, 11 is printed toshow the layout of the tubing or cabling 12, with a warning toinstallers not to insert fixing screws through the line of the tubing orcabling 12.

Each panel 10, 11 is of a bonded particulate material or of some othersolid material such as plywood. Each panel 10, 11 may, for example, beof chipboard or fibreboard or of wood shavings bonded together by aresin and is formed so that it can be installed with standardmass-produced wall or floor panels, such mass-produced panels typicallyhaving tongued and grooved edges to enable them to be assembled closelytogether. Each panel 10, 11 thus has similar tongues 13 along one endand one side and grooves 14 along the other end and other side.

FIG. 1A shows an alternative method of forming the bends in the tubingor cabling 12. Each bend can then have a larger radius of curvature thanis the case with the arrangement shown in FIGS. 1 and 2. Thus, if thestraight portions of the tube or cabling 12 are disposed 100 mm. apart,the bends can be formed with a radius of curvature of 80 mm. Thisfacilitates bending of tubes through which a heating or cooling fluid isto be passed.

FIG. 3, which is a cross-sectional view of the panel 10, shows onemethod of construction and the general form of the tongues 13 and thegrooves 14. The panel 10 is produced from two thinner panels 15 and 16each of which has been machined or otherwise formed with a serpentinechannel 17, the channel 17 in one thinner panel being the mirror imageof the channel 17 in the other thinner panel. The tubing or electriccabling 12 is introduced into one of the channels 17 and then the twothinner panels 15 and 16 are glued or otherwise fixed together so as toembed the tubing or cabling 12 within the structure of the formed panel10.

It is important that the machining or forming of the channels 17 isaccurate to suit the external diameter of the tubing or electric cabling12 to ensure that there is good thermal contact between the outside ofthe tubing or cabling 12 and the inside of each channel 17. For thisreason, it is recommended that, if the heating/cooling tubing orelectrical cabling is circular in section, the base of each of thechannels 17 should be semi-circular in section.

FIG. 4, which is a cross-sectional view of the panel 11, shows anothermethod of construction, in which a full-thickness panel has beenmachined or formed from one face to create a serpentine channel 18 intowhich the tubing or electric cabling 12 has been pressed. It is againimportant that the machining of the channel 18 is accurate to suit theexternal diameter of the tubing or electric cabling 12, to ensure thatthere is good thermal contact between the outside of the tubing orcabling 12 and the inside of the channel 18. For this reason, it isrecommended that the channel 18 should be machined or otherwise formedwith a bottom profile which is appropriate to the section of the tubingor cabling 12. With this method of construction, the machined or formeddepth of the channel 18 needs to be approximately equal to the externaldiameter of the tubing or cabling 12. Optionally, the tubing or cabling12 may be covered with a protective or conductive cement/plaster filling19.

After the tubing or cabling 12 has been located in the channel 18 andthe optional filling 19 has been applied if required, a thin sheet 9 ofaluminium foil can be bonded to the underside of the panel 11 so as tocover substantially the whole of the panel 11. The sheet 9 of foil willcontact the tubing or cabling 12 and/or the filling 19 and will avoiddirect contact of the atmosphere with the tubing or cabling 12 and/orthe filling 19. The sheet 9 of aluminium foil will act as a thermalreflector, rather than as a radiator, so as to ensure that theproportion of the heat generated within the tubing or cabling 12 whichis radiated from the upper surface of the panel 11 is greater than wouldotherwise be the case. Thus, a sheet of aluminium foil (not shown) couldalso be bonded to the underside of the panel 10 shown in FIGS. 1 and 3to increase the performance of the upper surface of the panel 10 as athermal radiator. The use of a sheet of aluminium foil over theunderside of a panel 10, 11 will also serve to improve thefire-resistance characteristics of the panel 10, 11.

Turning next to FIG. 5, this shows a corner of the panel 10 and theprovision of a rebate 20 which is machined or formed in the underside ofthe panel 10 at the point at which the embedded tubing or electriccabling 12 enters or leaves the panel 10. The rebate 20 comprises a slotwhich is slightly wider than the external diameter of the embeddedtubing or cabling 12 and has a length to suit the characteristics of thetubing or cabling 12 such as to permit the end of the tubing or cabling12 to be positioned without undue strain in the tubing or cabling 12 adistance below the underside of the panel 10 approximately equal to thethickness of the panel 10. This enables connection of the tubing orcabling 12 to the tubing or cabling of other panels or to flow andreturn supply pipes or to a power supply feed, as described in moredetail below.

As shown in FIG. 6, no rebate as such is required for the panel 11,since the method of construction of the panel 11 (as illustrated in FIG.4) is such that the tubing or electric cabling 12 is pressed into afull-length machined or formed channel 18 and, to effect connections tothe tubing or electric cabling 12, the tubing or electric cabling merelyhas to be pulled out of the channel 18 for a short distance back fromthe edge of the panel 11. However, if the tubing or electric cabling 12has been further located by the optional filling 19, care must be takento ensure that no such filling is used for the end portion 21 of thechannel 18.

FIG. 7 shows how connections are made between the tubing or electriccabling 12 embedded within a panel 10, 11 and flow and return supplypipes 22 and 23 (or power supply cables 24 and 25). A pair of panels 10or 11 are placed on a layer of insulation material 26 laid on top of afirm base (not shown), for example, a concrete base. The panels 10 or 11are positioned one on each side of a proprietary conduit 27 which isused to bring the flow and return pipes 22 and 23 or the power supplycables 24 and 25 to a position adjacent an end of a panel 10 or 11.

An aperture is made within the walling of the conduit 27 adjacent towhere the tubing or cabling 12 enters or leaves the end of the panel 10or 11. The end of the tubing or cabling 12 is then eased out of eitherthe rebate 20 or the end portion 21 of the channel 18 and positionedwithin the conduit 27 via this aperture. The tubing or cabling 12 isthen connected by means of a tube coupling 28 to the appropriate pipe 19or 20 or by means of an electrical connector 29 to the power supplycables 24 and 25. The conduit 27 is then fitted with its proprietarycapping 30, for example, a plywood capping held in position by fixingscrews 31.

FIG. 8 shows how connections are made between the tubing or electriccabling 12 embedded within a panel 10, 11 and a flow or return supplypipe 32 or a power supply cable 33, when the panels 10, 11 are installedon top of timber joists or battens 34.

When installing floor or wall panels, it is customary to position thejoints between the ends of adjacent panels so that they coincide withthe top of a joist or batten 34. A slot 35 having a width slightlygreater than the external diameter of the tubing or electric cabling 12is cut into the top of the joist or batten 34 adjacent to the positionat which the tubing or electric cabling 12 enters or leaves the end ofthe panel 10 or 11. A pipe coupling 36 or an electric connector 37 islocated adjacent the joist or batten 34 and the depth of the slot 35 issuch as to suit the dimensions of the coupling 36 or connector 37. Theend of the tubing or electric cabling 12 is then eased out of the bodyof the panel 10, 11, this being facilitated by the arrangements shown inFIGS. 5 and 6. The tubing or electric cabling 12 is then connected tothe flow or return pipe 32 or to the power supply cable 33 using thecoupling 36 or the connector 37.

Wherever possible, it is preferred that a plain, industry-standard panel38 is positioned above the couplings 36 or connectors 37 and fitted insuch a way that it is removable, in order that access can be obtained tothe couplings 36 and connectors 37. The ends of the panels 10, 11 and 38can then be fixed to the joists or battens 34 using screws 39 againtaking care to ensure that the screws 39 are so positioned as to avoiddamaging the tubing or cabling 12.

If the flow or return pipes 32 or the electric supply cables 33 must berun below the floor to locations adjacent to the ends of panels 10 or11, where they must run in the direction of the line of the joists 34,it is recommended that they be clipped to the tops of the joists 34using proprietary P-clips 40 in the manner shown in FIG. 9. Where thepipes 32 or cables 33 must run across the line of the joists 34, it isrecommended that they be located in slots 41 cut neatly into the tops ofthe joists 34 in the manner shown in FIG. 10.

In an alternative arrangement, a hole is drilled on the neutral axis ofthe joist and the pipe or cable is passed through this drilled hole.

FIG. 11 shows a typical floor installation which includes four panels 10and ten plain, industry-standard panels 38 laid on top of a layer ofinsulation (not shown). The heat exchange elements within the panels 10are arranged in parallel as shown in FIG. 12 and are connected to thesupply and return pipes 32 or to the power supply cables 33 in themanner illustrated in FIG. 7. Conduits 27 with their associated cappingmembers 30 are used along three sides of the installation as shown inFIG. 11.

The sequence of installation is as follows:

a) the conduits 27 are positioned on the three sides of the installationand are fixed to the floor, for example, a concrete base,

b) if the panels 10 and 38 do not include a layer of insulation, aninsulation layer is then laid, and

c) the panels 10 and 38 are then laid in the configuration shown in thesequence determined by the tongue and groove formations on the panels.

Whenever a panel 10 is laid, apertures are made in the walling of theadjacent conduit 27 near the points at which the tubing or electriccabling 12 enters or leaves the panel 10 and the tubing or electriccabling is fed through such apertures into the conduit 27. When all thepanels 10 and 38 are in position, the flow and return supply pipes 32 orthe electrical supply cables 33 are run into the conduits 27 to pointsadjacent to the ends of the panels 10 and connections made as describedabove. When such connections have been made and tested, the cappingmembers 30 for the conduits 27 are screwed into position.

The number of panels 10 required for a given floor can be determinedfrom a consideration of the size and usage of the floor and the spaceabove it. The arrangement shown in FIG. 11 is, however, that of atypical installation. FIG. 12 shows how the heat exchange elementswithin the panels 10 are linked in parallel so that each has the samerelationship to the flow and return supply.

Turning next to FIG. 13, this shows a typical installation comprisingfour panels 10 and eight plain, industry-standard panels or boards 38.The method of interconnection of the heat exchange elements within thepanels 10 and the flow and return supply pipes 32 or the electricalcabling 33 is as shown in FIG. 8. The positions of the timber joists 34are indicated in FIG. 13 and it is to be noted that the junctionsbetween the ends of the panels 10 and 38 coincide with the tops of thejoists 34.

The boards or panels 10 and 38 are indicated in FIG. 13 by the lettersA, B, C, D, E, F, G, H, J, K, L and M. Panels D, E, F and H are in theform of modules which incorporate serpentine heat exchange elements asdescribed above, whilst the other panels are industry-standard floorpanels. The boards or panels are positioned together to form part of thefloor structure within which the modules are interlinked with a flowdiagram for the heat exchange elements as shown in FIG. 14.

The sequence of installation is as follows:

a) Boards A and B are laid first, followed by boards C and D, the latterbeing the first of the boards containing a heating element.

b) Board E is next, taking care to position the tubing or electriccabling of that board across and along the joists 34 to below where theboards L and M will be located.

c) Board F is next, again taking care to position the tubing or electriccabling from that board into the spaces below boards L and M.

d) Boards H and G will be next, followed by board J.

e) At this stage, the flow and return pipes 32 or the electrical powersupply cables 33 can be laid and the connections made to the tubing orcabling in boards D, E, F and H. The connections are then tested.

f) Board K is then fitted, followed by boards L and M which are fittedin such a way that they are removable.

The number of boards or panels which need to incorporate heat exchangeelements can be determined from a consideration of the size and usage ofthe floor and the space above it. The overall energy efficiency can beimproved if some form of insulation is introduced between the joists 34before the boards or panels are laid and if those boards or panels whichincorporate a heat exchange element are lined on their undersides with asheet of aluminium foil, as explained above in relation to FIG. 4.

FIG. 15 shows how a panel 10, 11 in accordance with the invention canform part of a composite board. The board 10, 11 is bonded to a layer ofinsulation material 42. With such a composite board, it is necessary toform not only a rebate in the underside of the panel 10, 11 but also arebate 43 in the layer of insulation material 42 so as to facilitateconnection of the embedded tubing or electric cabling 12 to the flow andreturn supply pipes or to the electricity supply.

A further form of composite board is shown in FIG. 16 and is designedfor use where its acoustic properties are important. Such acousticboards are increasingly specified for multiple-occupation buildings. Asshown, a panel 10 is bonded by adhesive discs 44 to a secondary board 45in such a way that an air gap 46 is created between the underside of thepanel 10 and the secondary board 45. This air gap 46 inhibits thetransmission of noise from above the panel 10 to the joists 34. Such acomposite board can have another layer 47, of felt-like material bondedto its underside.

The composite board of FIG. 16 will be formed with a rebate 43 not onlyin the underside of the panel 10 but also in the secondary board 45 andin the layer 47 of felt-like material. FIG. 16 also shows how the timberfloor joist has to be notched at 48 to enable connections to be made tothe embedded tubing or electric cabling 12. As explained above inrelation to FIG. 10, a hole could alternatively be drilled on theneutral axis of the joist to receive the tubing or cabling 12.

With underfloor heating systems which have hitherto been available, ithas been quite impossible to install them in conjunction with acousticboards such as that illustrated, because the air gap which forms part ofthe acoustic board has inhibited the conduction of heat through to thefloor surface. However, with the panel of the present invention, itbecomes possible to manufacture an acoustic board with integralunderfloor heating/cooling. Moreover the presence of such an air gaphelps prevent loss of heat through to the underside of the compositeboard.

A further method of producing a panel is shown in FIG. 17. This involvesthe use of two half-thickness panels 49 and 50 of fibreboard, chipboardor the like between which a plastic sheet 52 is sandwiched. The sheet 52has a resistance element 53 printed on it or otherwise applied to it andthe resistance element 53 includes a pair of parallel relatively thickend members 54 between which there extend a large number of relativelythin lines 55 of higher resistance than the end members 54. The panel ofFIG. 17 is produced by bonding the three layers together with,optionally, a thin sheet of aluminium foil (not shown) on the undersideof the panel so as to act as a reflector, as described above in relationto FIG. 4. In use, the resistance element 53 will be connected to thepower supply and the arrangement of the thin lines 55 will be such thatthe panel is heated substantially uniformly throughout its area. Asthere are a large number of thin lines 55 disposed in parallel, theeffectiveness of the resistance element 53 will be affected onlymarginally if one or two of such lines should become ruptured.

In a further method of producing a panel, not shown in the drawings, anarrangement similar to that shown in FIG. 17 is employed except that,instead of an electrical resistance element, an assembly of plastictubes is employed, said assembly comprising a pair of end members havingan internal diameter of the order of 7 mm. with a large number ofnarrow, almost capillary-like tubes interconnecting the end members, thenarrow tubes having an internal diameter of 1 or 2 mm.

The present invention has a number of advantages, as follows:

a) the use of the panels or boards of the present invention inconjunction with standard, mass-produced boards which would be usedanyway, results in the heating/cooling system for a building beingincorporated automatically as part of the construction or refurbishmentprogramme. It does not have to be added as a separate activity.

b) the heating/cooling system which is created has all of the advantagesassociated with underfloor heating/cooling systems, for example, highcomfort levels without draughts, high energy efficiency, unclutteredwalls, reduced decoration costs and higher relative humidity, thusproviding less dryness. Thus, although it might have been expected fromexperience of present underfloor heating systems that the separation ofsuch small diameter tubing, i.e. tubing of from 5 to 9 mm. internaldiameter, so widely in a known poor conductor, such as chipboard orfibreboard, would result in the heating/cooling effect being localisedto the immediate vicinity of the tubing, with the consequence that thepanel would not radiate. Contrary to such expectations, it has beenfound that, provided good physical contact is established between thetubing and the body of the panel, not only is thermal conductionsufficiently good to induce the panel to radiate, but that the requiredtop surface temperature for heating comfort to be achieved can beobtained with water temperatures lower than those used in presentunderfloor heating systems.

c) the use of the panels or boards and the method of the presentinvention substantially reduces the cost of installing underfloorheating/cooling systems, which has been a principal factor inhibitingtheir wide-scale use. Thus, the cost of supplying and laying a layer ofinsulation on top of which panels are laid in a manner such as isillustrated in FIG. 11 or FIG. 13 will be comparable to the combinedcost of laying a solid screeded floor and installing a conventionalconvection heating system. In addition, for timber floors laid onjoists, the combined cost of supplying and laying a complete floor of"industry-standard" panels and supplying a conventional convectionheating system will be greater than the cost of supplying and installingthe same floor provided with underfloor heating in a manner such as isillustrated in FIG. 11 or FIG. 13.

Whereas convection systems which use radiators require water heated to atemperature of approximately 80° C., the currently available underfloorheating systems provide complete comfort with floor temperatures ofbetween 23° and 25° C. and this can be achieved using water at atemperature of 60° C. This is much lower than for radiator systems andis the principal reason why the current underfloor heating systems showfuel savings, as compared with equivalent radiator systems, of between40 and 50%.

In contrast with this, when using the panels of the present inventionwhich incorporate small-diameter tubing through which hot water ispumped, the required floor surface temperature can be achieved withwater temperatures as low as 45° to 50° C. When the much lower watervolumes, as compared with radiator systems or underfloor heating systemsusing large diameter pipes, are also taken into account, it can be seenthat a heating system in accordance with the present invention is verymuch more economical than radiator systems and significantly moreenergy-efficient than existing underfloor heating systems.

The panels of the present invention are almost identical in form anddimension to "industry-standard" floor and wall panels. They are as easyto install as "industry-standard" floor and wall panels and can beconnected into a heating system more easily than radiators. They canalso be used as a cooling system in, for example, an office block. Ifwater from a source of chilled water is fed through the tubing withinpanels forming part of either a wall or floor, the cooling effectobtained in this way will maintain office premises at a comfortableworking temperature, even during a heat wave.

The panels of the present invention can also be used as components ofmore sophisticated flooring panels, as explained above with particularreference to FIGS. 15 and 16.

The heating system of the present invention also produces a heatingeffect very quickly. With most forms of heating system, there is atime-lag between turning on the heating and the production of anoticeable heating effect. With large diameter piping underfloor heatingsystems, this delay is such that most such installations have to be runalmost continuously.

A panel in accordance with the present invention has very little thermalinertia and it is an effective radiator. Consequently, the panel startsto produce a heating effect within approximately ten to fifteen minutesof start-up and, equally importantly, begins to cool within a similarperiod after shut-down. The importance of this is that there is littleinvestment in energy left behind after shut-down, which is not the casewith most other forms of heating system. Thus, as applied to, forexample, a heating system for an office block, the heating system can beturned on shortly before the start of the working day and then turnedoff at the end of the working day without excessive heat losses.

I claim:
 1. A method of installing a heating/cooling system which includes:a) providing a plurality of solid panels each of which comprises a solid body having an upper surface and a lower surface some of the panels being in the form of heating/cooling modules each of which incorporates a heat exchange element of serpentine form disposed within a downwardly facing serpentine channel in the body of the panel so as to be spaced from the upper surface of the panel and located in thermal contact with the body of the panel, while others of said panels do not contain a heat exchange element, b) the panels containing heat exchange elements being of the same size and external configuration ad those not containing heat exchange elements, c) joining said panels together to form a structure, and d) interlinking the heat exchange elements of said modules, and in which:i) each serpentine channel is formed in the undersurface of the respective panel, ii) the undersurface of each panel which incorporates a heating element is covered by a sheet of reflective metal foil, and iii) the upper surface of each panel which incorporates a heating element is marked to indicate the location of the heating element.
 2. A method of installing a heating/cooling system which includes;a) providing a plurality of solid panels each of which comprises a solid body having an upper surface and a lower surface, some of the panels being in the form of heating/cooling modules each of which incorporates a heat exchange element of serpentine form disposed within a downwardly facing serpentine channel in the body of the panel so as to be spaced from the upper surface of the panel and located in thermal contact with the body of the panel, while others of said panels do not contain a heat exchange element, b) the panels cooling heat exchange elements being of the same size and external configuration as those not containing heat exchange elements, c) joining said panels together to form a structure, and d) interlinking the heat exchange elements of said modules, and in which the heat exchange elements comprise plastic tubing through which a heating/cooling medium is passed, the panels are said on joists to form a floor, the elements are connected to supply and return pipes located between the joists and the connections to said supply and return pipes are effected beneath panels which do not incorporate heat exchange elements.
 3. A central heating/cooling system comprising at least one source of heating/cooling fluid with flow and return pipes and heat exchange mean, wherein the heat exchange means comprises at least two heat exchange elements each incorporated within a solid panel having an upper surface add a lower surface and forming part of a floor of cooperating panels, said floor also including a plurality of panels which do not contain heat exchange elements, the panels which incorporate heat exchange elements being of the same size and configuration as those which do not incorporate heat exchange elements, each of the heat exchange elements being of serpentine form and located as a close fit in a downwardly facing channel in the panel so as to be spaced from the upper surface of the panel means being provided for connecting the heat exchange elements to each other and to the source, and in which:a) the panels are formed of bonded particulate material, b) the panels which incorporate heat exchange elements each have their lower surfaces covered by a sheet of reflective metal foil, and c) the panels which incorporate heat exchange elements have their upper surfaces marked to indicate the locations of the heat exchange elements. 